Theron will play Libby Day, a woman whose family was slaughtered in what appeared to be a Satanic cult ritual when she was seven. Back in the day, she pointed to her brother as the culprit, testifying against him in court. Now, 25 years later, the Kill Club, a group obsessed with notorious crimes, confronts her with some searching questions about what actually happened that day. Libby’s inspired to dig into the matter herself and discovers some potential new suspects.

If she signs, Moretz will be a young woman named Diondra, who knows Libby’s brother, Ben.